Development of a dynamic LCA approach for the freshwater ecotoxicity impact of metals and application to a case study regarding zinc fertilization

Purpose

Temporal variability is a major source of uncertainty in current life cycle assessment (LCA) practice. In this paper, the recently developed dynamic LCA approach is adapted to assess freshwater ecotoxicity impacts of metals. The objective is to provide relevant information regarding the distribution and magnitude of metal impacts over time and to show whether the dynamic approach significantly influences the conclusions of an LCA. An LCA of zinc fertilization in agriculture was therefore carried out.

Methods

Dynamic LCA is based on the temporal disaggregation of the inventory, which is then assessed using time-horizon-dependent characterization factors. The USEtox multimedia fate model is used to develop time-horizon-dependent characterization factors for the freshwater ecotoxicity impact of 18 metals. Mass balance equations are solved dynamically to obtain fate factors as a function of time, providing both instantaneous (impact at time t following a pulse emission) and cumulative (total time-integrated impact following a pulse emission) characterization factors (CFs).

Results and discussion

Time-horizon-dependent CFs for freshwater ecotoxicity depend on the emission compartment and the metal itself. The two variables clearly influence metal fate aspects such as the maximum mass loading reaching freshwater and the persistence time of metals into this compartment. The time needed to reach the total impact for each metal may exceed thousands of years, so the time horizon used in the analysis constitutes a determining factor. The case study reveals that the results of a classical LCA are always higher than those obtained from a dynamic LCA, especially for short time horizons. For instance, at the end of a 100-year fertilization treatment, only 25 % of the impacts obtained through traditional LCA occurred.

Conclusions

Results show that dynamic LCA enables assessing freshwater ecotoxicity impacts of metals over time, allowing decision makers to test the sensitivity of their results to the choice of a time horizon. For the particular case study of zinc fertilization over a period of 20 years, the use of time-horizon-dependent CFs is more important in determining the dynamics of impacts than the timing of emission.     

A life cycle assessment study of a Canadian post-combustion carbon dioxide capture process system

Purpose

While carbon dioxide capture and storage (CCS) has been widely recognized as a useful technology for mitigating greenhouse gas emissions, it is necessary to evaluate the environmental performance of CCS from a full life cycle perspective to comprehensively understand its environmental impacts. The primary research objective is to conduct a study on life cycle assessment of the post-combustion carbon dioxide capture process based on data from SaskPower’s electricity generation station at the Boundary Dam in Saskatchewan, Canada. A secondary objective of this study is to identify the life cycle impact assessment (LCIA) methodology which is most suitable for the assessment of carbon dioxide capture technology integrated with the power generation system in the Canadian context.

Methods

The study takes a comparative approach by including three scenarios of carbon dioxide capture at the electricity generation station: no carbon dioxide capture (“no capture”), partial capture (“retrofit”), and fully integrated carbon dioxide capture of the entire facility (“capture”). The four LCIA methods of EDIP 97, CML2001, IMPACT2002+, and TRACI are used to convert existing inventory data into environmental impacts. The LCIA results from the four methods are compared and interpreted based on midpoint categories.

Results and discussion

The LCA results showed an increase in the retrofit and capture scenarios compared to the no capture scenario in the impact categories of eutrophication air, ecotoxicity water, ecotoxicity ground surface soil, eutrophication water, human health cancer ground surface soil, human health cancer water, human health noncancer ground surface soil, ozone depletion air, human health noncancer water, and ionizing radiation. The reductions were observed in the retrofit and capture scenarios in the impact categories of acidification, human health criteria air-point source, human health noncancer air, ecotoxicity air, global warming, human health cancer air, and respiratory effects.

Conclusions

Although the four LCIA methodologies significantly differ in terms of reference substances used for individual impact categories, all (TRACI, IMPACT2002+, CML2001, and EDIP 97) showed similar results in all impact categories.     

Life cycle assessment of a waste lubricant oil management system

Purpose

This paper compares 16 waste lubricant oil (WLO) systems (15 management alternatives and a system in use in Portugal) using a life cycle assessment (LCA). The alternatives tested use various mild processing techniques and recovery options: recycling during expanded clay production, recycling and electric energy production, re-refining, energy recovery during cement production, and energy recovery during expanded clay production.

Methods

The proposed 15 alternatives and the actual present day situation were analyzed using LCA software UMBERTO 5.5, applied to eight environmental impact categories. The LCA included an expansion system to accommodate co-products.

Results

The results show that mild processing with low liquid gas fuel consumption and re-refining is the best option to manage WLO with regard to abiotic depletion, eutrophication, global warming, and human toxicity environmental impacts. A further environmental option is to treat the WLO using the same mild processing technique, but then send it to expanded clay recycling to be used as a fuel in expanded clay production, as this is the best option regarding freshwater sedimental ecotoxicity, freshwater aquatic ecotoxicity, and acidification.

Conclusions

It is recommended that there is a shift away from recycling and electric energy production. Although sensitivity analysis shows re-refining and energy recovery in expanded clay production are sensitive to unit location and substituted products emission factors, the LCA analysis as a whole shows that both options are good recovery options; re-refining is the preferable option because it is closer to the New Waste Framework Directive waste hierarchy principle.     

Potential for optimized production and use of rapeseed biodiesel. Based on a comprehensive real-time LCA case study in Denmark with multiple pathways

Purpose

Several factors contribute to the current increased focus on alternative fuels such as biodiesel, including an increasing awareness of the environmental impact of petrochemical (PC) oil products such as PC diesel, the continuously increasing price of PC oil, and the depletion of PC oil. For these reasons, the European Union has enacted a directive requiring each member state to ensure that the share of energy from renewable sources in transport be at least 10 % of the final consumption of energy by 2020 (The European Parliament and the Council 2009). This LCA study assesses the specific environmental impacts from the production and use of biodiesel as it is today (real-time), based on rapeseed oil and different types of alcohols, and using technologies that are currently available or will be available shortly. Different options are evaluated for the environmental improvement of production methods. The modeling of the LCA is based on a specific Danish biodiesel production facility.

Methods

The functional unit is “1,000 km transportation for a standard passenger car.” All relevant process stages are included, such as rapeseed production including carbon sequestration and N₂O balances, and transportation of products used in the life cycle of biodiesel. System expansion has been used to handle allocation issues.

Results and discussion

The climate change potential from the production and use of biodiesel today is 57 kg CO₂-eq/1,000 km, while PC diesel is 214 kg CO₂-eq/1,000 km. Options for improvement include the increased use of residual straw from rapeseed fields for combustion in a power plant where carbon sequestration is considered, and a change in transesterification from a conventional process to an enzymatic process when using bioethanol instead of PC methanol. This research also evaluates results for land use, respiratory inorganics potential, human toxicity (carc) potential, ecotoxicity (freshwater) potential, and aquatic eutrophication (N) potential. Different sources for uncertainty are evaluated, and the largest drivers for uncertainty are the assumptions embedded into the substitution effects. The results presented should not be interpreted as a blueprint for the increased production of biodiesel but rather as a benchmarking point for the present, actual impact in a well-to-wheels perspective of biodiesel, with options for improving production and use.

Conclusions

Based on this analysis, we recommend investigating additional options and incentives regarding the increased use of rape straw, particularly considering the carbon sequestration issues (from the perspective of potential climate change) of using bioalcohol instead of PC alcohol for the transesterification process.     

Life cycle assessment of a biobased chainsaw oil made on the farm in Wallonia

Purpose

The environmental issue is a particular concern for chainsaw oils because these fluids represent a total loss system. The aim of this study is to quantify the environmental impacts of a biobased chainsaw oil made on the farm in Wallonia (a region of Belgium) and to compare it with a model mineral chainsaw oil. With this study, the aim is also to participate in the development of the life cycle assessment (LCA) methodology applied to the biolubricant sector since LCAs on these products are quite limited and rarely sufficiently detailed.

Method

In this LCA, the attributional approach is applied. Seven impact categories are studied. The methods for life cycle impact assessment are IPCC, ReCiPe, CML and USEtox. The functional unit is 1 kg of base oil. Seven sensitivity analyses are performed.

Results and discussion

Results indicate that the biobased chainsaw oil made on the farm has a lower impact for the global warming potential, the abiotic depletion potential, the ozone depletion potential and the photochemical oxidation potential. On the contrary, it has larger acidification, aquatic eutrophication and aquatic ecotoxicity potential impacts. Regarding the contribution of the life cycle stages of the biobased chainsaw oil, the agricultural stage causes the highest contribution in all impact categories. For the mineral chainsaw oil, the refining stage is preponderant for all impact categories except for the global warming potential for which the end-of-life stage contributes the most. When taking additives into account, conclusions regarding the comparison between the oils are not reversed. Even if it was necessary to consume more biobased than mineral chainsaw oil, conclusions regarding the comparison of the oils would not be reversed. In the same way, a different allocation procedure for rapeseed oil and rape meal, a different rape seeds yield or different extraction yields in the refining stage of the mineral base oil do not change the results of the comparison. For the biobased chainsaw oil, the substitution of only one active substance in the agricultural stage could result in an important decrease of the freshwater ecotoxicity impact.

Conclusions

The biobased chainsaw oil has a lower impact in four out of the seven impact categories and a higher impact in three impact categories. By providing a detailed LCA on a biobased chainsaw oil, this study contributes to the development of LCA applied to biobased lubricants.     

Life cycle assessment (LCA) applied to the process industry: a review

Purpose

Life cycle assessment (LCA) methodology is a well-established analytical method to quantify environmental impacts, which has been mainly applied to products. However, recent literature would suggest that it has also the potential as an analysis and design tool for processes, and stresses that one of the biggest challenges of this decade in the field of process systems engineering (PSE) is the development of tools for environmental considerations.

Method

This article attempts to give an overview of the integration of LCA methodology in the context of industrial ecology, and focuses on the use of this methodology for environmental considerations concerning process design and optimization.

Results

The review identifies that LCA is often used as a multi-objective optimization of processes: practitioners use LCA to obtain the inventory and inject the results into the optimization model. It also shows that most of the LCA studies undertaken on process analysis consider the unit processes as black boxes and build the inventory analysis on fixed operating conditions.

Conclusions

The article highlights the interest to better assimilate PSE tools with LCA methodology, in order to produce a more detailed analysis. This will allow optimizing the influence of process operating conditions on environmental impacts and including detailed environmental results into process industry.     

A hybrid life cycle assessment of water treatment chemicals: an Australian experience

Purpose

Life cycle assessment (LCA) of chemicals is usually developed using a process-based approach. In this paper, we develop a tiered hybrid LCA of water treatment chemicals combining the specificity of process data with the holistic nature of input–output analysis (IOA). We compare these results with process and input–output models for the most commonly used chemicals in the Australian water industry to identify the direct and indirect environmental impacts associated with the manufacturing of these materials.

Methods

We have improved a previous Australian hybrid LCA model by updating the environmental indicators and expanding the number of included industry sectors of the economy. We also present an alternative way to estimate the expenditure vectors to the service sectors of the economy when financial data are not available. Process-based, input–output and hybrid results were calculated for caustic soda, sodium hypochlorite, ferric chloride, aluminium sulphate, fluorosilicic acid, calcium oxide and chlorine gas. The functional unit is the same for each chemical: the production of 1 tonne in the year 2008.

Results and discussion

We have provided results for seven impact categories: global warming potential; primary energy; water use; marine, freshwater and terrestrial ecotoxicity potentials and human toxicity potential. Results are compared with previous IOA and hybrid studies. A sensitivity analysis of the results to assumed wholesale prices is included. We also present insights regarding how hybrid modelling helps to overcome the limitations of using IO- or process-based modelling individually.

Conclusions and recommendations

The advantages of using hybrid modelling have been demonstrated for water treatment chemicals by expanding the boundaries of process-based modelling and also by reducing the sensitivity of IOA to fluctuations in prices of raw materials used for the production of these industrial commodities. The development of robust hybrid life cycle inventory databases is paramount if hybrid modelling is to become a standard practice in attributional LCA.     

Environmental assessment of the production and addition of bioethanol produced from <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> to gasoline in Chile

Purpose

Bioethanol is not currently produced in Chile. However, mixtures of bioethanol-gasoline at 2 and 5 % have been authorized. The production and use of the bioethanol-gasoline blend “E5” has been assessed using life cycle assessment (LCA) with the aim to compare the environmental profiles of bioethanol produced from Eucalyptus globulus with gasoline in Chile and to determine the potential of this biofuel-replacing gasoline in the transport sector.

Methods

The standard framework of LCA described by ISO was selected to assess the ecological burdens derived from the biofuel production using the SimaPro v7.8 software. The system boundaries included eucalyptus cultivation, bioethanol production, E5 blend production, and final use of E5. The inventory data for Eucalyptus cultivation were previously collected through surveys with forest managers. Inventory data for bioethanol production were obtained by process simulation models using Aspen Plus v7.1, and for non-simulated or modeled information, secondary information (scientific articles and reports) was used. Conventional gasoline, produced and used in Chile, was used as base scenario for comparison with E5 scenario.

Results and discussion

The environmental results showed reduction of the environmental impacts in most of the assessed categories when E5 blend is assessed and compared with gasoline. Reduction was evident for climate change, photochemical oxidation formation, terrestrial acidification, marine eutrophication, terrestrial ecotoxicity, marine ecotoxicity, depletion of water, and fossil resources. However, there was an increase in other impact categories, such as ozone layer depletion, human toxicity, terrestrial ecotoxicity, and marine eutrophication. The hotspots for E5 blend were the blending production and the combustion in the engine, whereas in the production process, the electricity production was the major contributor to most of the impact categories. When increasing the bioethanol content from E5 to E10 blend, the environmental impact increases in most of the evaluated categories except in the CC, WD, and FD categories. However, compared with other studies related to wood-based E10, the values for the environmental impacts obtained were lower than the reported.

Conclusions

The use of E5 blend can help to reduce the environmental impact in 8 of the 12 categories analyzed. Environmental impacts obtained are lower compared with other studies reported for E10 blend production from wood resources.

     

Inclusion of uncertainty in the LCA comparison of different cherry tomato production scenarios

Purpose

Knowledge regarding environmental impacts of agricultural systems is required. Consideration of uncertainty in life cycle assessment (LCA) provides additional scientific information for decision making. The aims of this study were to compare the environmental impacts of different growing cherry tomato cultivation scenarios under Mediterranean conditions and to assess the uncertainty associated to the different agricultural production scenarios.

Materials and methods

The burdens associated to cherry tomato production were calculated and evaluated by the LCA methodology. The functional unit (FU) chosen for this study was the mass unit of 1 t of commercial loose cherry tomatoes. This study included the quantitative uncertainty analysis through Monte Carlo simulation. Three scenarios were considered: greenhouse (GH), screenhouse (SH), and open field (OF). The flows and processes of the product scenario were structured in several sections: structure, auxiliary equipment, fertilizers, crop management, pesticides, and waste management. Six midpoint impact categories were selected for their relevance: climate change, terrestrial acidification, marine eutrophication, metal depletion, and fossil depletion using the impact evaluation method Recipe Midpoint and ecotoxicity using USEtox.

Results and discussion

The structure, auxiliary equipment, and fertilizers produced the largest environmental impacts in cherry tomato production. The greatest impact in these stages was found in the manufacture and drawing of the steel structures, manufacture of perlite, the amount of HDPE plastics used, and the electricity consumed by the irrigation system and the manufacture and application of fertilizers. GH was the cropping scenario with the largest environmental impact in most categories (varying from 18 and 37% higher than SH and OF, respectively, in metal depletion, to 96% higher than SH and OF, in eutrophication). OF showed the highest uncertainty in ecotoxicity, with a bandwidth of 60 CTUe and a probability of 100 and 99.4% to be higher than GH and SH, respectively.

Conclusions

The LCA was used to improve the identification and evaluation of the environmental burdens for cherry tomato production in the Mediterranean area. This study demonstrates the significance of conducting uncertainty analyses for comparative LCAs used in comparative relative product environmental impacts.

     

Life cycle assessment evaluation of green product labeling systems for residential construction

Purpose

Life cycle assessment (LCA) is a tool that can be utilized to holistically evaluate novel trends in the construction industry and the associated environmental impacts. Green labels are awarded by several organizations based on single or multiple attributes. The use of multi-criteria labels is a good start to the labeling process as opposed to single criteria labels that ignore a majority of impacts from products. Life cycle thinking, in theory, has the potential to improve the environmental impacts of labeling systems. However, LCA databases currently are lacking in detailed information about products or sometimes provide conflicting information.

Method

This study compares generic and green-labeled carpets, paints, and linoleum flooring using the Building for Environmental and Economic Sustainability (BEES) LCA database. The results from these comparisons are not intuitive and are contradictory in several impact categories with respect to the greenness of the product. Other data sources such as environmental product declarations and ecoinvent are also compared with the BEES data to compare the results and display the disparity in the databases.

Results

This study shows that partial LCAs focused on the production and transportation phase help in identifying improvements in the product itself and improving the manufacturing process but the results are uncertain and dependent upon the source or database. Inconsistencies in the data and missing categories add to the ambiguity in LCA results.

Conclusions

While life cycle thinking in concept can improve the green labeling systems available, LCA data is lacking. Therefore, LCA data and tools need to improve to support and enable market trends.     

Do wood-based panels made with agro-industrial residues provide environmentally benign alternatives? An LCA case study of sugarcane bagasse addition to particle board manufacturing

Purpose

Sugarcane bagasse is one of the main agro-industrial residues which can be used to produce wood-based panels. However, more investigations related to its environmental performance assessment are needed, focusing on questions such as: Does it provide environmental benefits? What are its main environmental impacts? Could it substitute wood as raw material? Accordingly, this paper presents a life cycle assessment (LCA) study of particle board manufactured with sugarcane bagasse residues.

Methods

The cradle-to-gate assessment of 1 m³ of particle board made with sugarcane bagasse (PSB) considered three main subsystems: bagasse generation, bagasse distribution, and PSB production. For the inventory of PSB, dataset from two previous LCA studies related to the conventional particle board production and the ethanol life cycle for the Brazilian context were used. The allocation criterion for the bagasse generation subsystem was 9.08 % (economic base). The potential environmental impact phase was assessed by applying the CML and USEtox methods. PSB was compared with the conventional particle board manufactured in Brazil by the categories of the CML and USETox, and including land use indicators. Finally, two scenarios were analyzed to evaluate the influence of the allocation criteria and the consumption of sugarcane bagasse.

Results and discussion

All hotspots identified by CML and USETox methods are mainly related to the PSB production subsystem (24–100 % of impacts) due to heavy fuel oil, electricity, and urea-formaldehyde resin supply chain. The bagasse generation subsystem was more relevant to the eutrophication category (75 % of impacts). The bagasse distribution subsystem was not relevant because the impacts on all categories were lower than 1 %. PSB can substitute the conventional particle board mainly because of its lower contribution to abiotic depletion and ecotoxicity. Regarding land use impacts, PSB showed lower values according to all indicators (38–40 % of all impacts), which is explained by the lower demand for land occupation in comparison to that of the traditional particle board.

Conclusions

PSB can replace the traditional particle board due to its better environmental performance. The analysis of the economic allocation criterion was relevant only for the EP category, being important to reduce diesel and N-based fertilizers use during sugarcane cultivation. Regarding the influence of the sugarcane bagasse consumption, it is suggested that the sugarcane bagasse be mixed up to 75 % during particle board manufacturing so that good quality properties and environmental performance of panels can be provided.     

An environmental comparison of biocomposite film based on orange peel-derived pectin jelly-corn starch and LDPE film: LCA and biodegradability

Purpose

A new biodegradable film, based on orange peel-derived pectin jelly and corn starch developed in our labs, was environmentally compared with a low-density polyethylene (LDPE) film. An environmental assessment was realized in two stages to individually determine the environmental impact resulting from production-shaping processes and the biodegradation performance of the films.

Methods

Firstly, a prospective cradle-to-gate life cycle assessment (LCA) was performed using a CML-IA method implemented in SimaPro 8.0.1. Secondly, an aerobic biodegradation was simulated as directly disposing of the films in soil according to ASTM D 5988–03. The functional unit considered in this study was 1 m² of packaging film. The films were compared for impact categories of abiotic depletion (elements and fossil fuel), global warming potential, ozone layer depletion, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity, photochemical oxidation, acidification, and eutrophication. A Monte Carlo simulation was realized to determine the uncertainty levels. According to impact assessment results and major sources of uncertainties, two predictive improvement scenarios were performed for commercial scale production and compared with biocomposite film at the laboratory scale.

Results and discussion

LCA results show that biocomposite film has a slightly higher impact than LDPE film for all categories with probabilities ranging between 50 and 100 % except for acidification. The categories that have uncertainty (terrestrial ecotoxicity, abiotic depletion (element), photochemical oxidation, human toxicity, and fresh water aquatic ecotoxicity) were mainly resulted from electricity consumption for extrusion and film forming and modified starch addition. These two processes are mainly responsible for the environmental impact of the biocomposite film.

Conclusions

Prospective LCA showed that improvement of the process in this manner would decrease the environmental impact. On the other hand, the maximum level of biodegradation achieved in the biocomposite film is 78.4 %, whereas that for the LDPE film is 40.4 % with CO₂ production rates of 1.97 and 1.17 mmol CO₂/day, respectively.

     

A review of life cycle assessments on wind energy systems

Purpose

Several life cycle assessments (LCAs) of wind energy published in recent years are reviewed to identify methodological differences and underlying assumptions.

Methods

A full comparative analysis of 12 studies were undertaken (ten peer-reviewed papers, one conference paper, and one industry report) regarding six fundamental factors (methods used, energy use accounting, quantification of energy production, energy performance and primary energy, natural resources, and recycling). Each factor is discussed in detail to highlight strengths and shortcomings of various approaches.

Results

Several potential issues are found concerning the way LCA methods are used for assessing energy performance and environmental impact of wind energy, as well as dealing with natural resource use and depletion. The potential to evaluate natural resource use and depletion impacts from wind energy appears to be poorly exploited or elaborated on in the reviewed studies. Estimations of energy performance and environmental impacts are critically analyzed and found to differ significantly.

Conclusions and recommendations

A continued discussion and development of LCA methodology for wind energy and other energy resources are encouraged. Efforts should be made to standardize methods and calculations. Inconsistent use of terminology and concepts among the analyzed studies are found and should be remedied. Different methods are generally used and the results are presented in diverse ways, making it difficult to compare studies with each other, but also with other renewable energy sources.     

LCA of energetic biomass utilization: actual projects and new developments—April 23, 2012, Berne, Switzerland

Introduction

In the last years, the use of biomass for energy purposes has been seen as a promising option to reduce the use of nonrenewable energy sources and the emissions of fossil carbon. However, LCA studies have shown that the energetic use of biomass also causes impacts on climate change and, furthermore, that different environmental issues arise, such as land use and agricultural emissions. While biomass is renewable, it is not an unlimited resource. Its use, to whatever purpose, must therefore be well studied to promote the most efficient option with the least environmental impacts. The 47th LCA Discussion Forum gathered several national and international speakers who provided a broad and qualified view on the topic.

Summary of the topics presented in DF 47

Several aspects of energetic biomass use from a range of projects financed by the Swiss Federal Office of Energy (SFOE) were presented in this Discussion Forum. The first session focused on important aspects of the agricultural biogas production like the use of high energy crops or catch crops as well as the influence of plant size on the environmental performance of biogas. In the second session, other possibilities of biomass treatment like direct combustion, composting, and incineration with municipal waste were presented. Topic of the first afternoon session was the update and harmonization of biomass inventories and the resulting new assessment of biofuels. The short presentations investigated some further aspects of the LCA of bioenergy like the assessment of spatial variation of greenhouse gas (GHG) emissions from bioenergy production in a country, the importance of indirect land use change emissions on the overall results, the assessment of alternative technologies to direct spreading of digestate or the updates of the car operation datasets in ecoinvent.

Conclusions

One main outcome of this Discussion Forum is that bioenergy is not environmentally friendly per se. In many cases, energetic use of biomass allows a reduction of GHG and fossil energy use. However, there is often a tradeoff with other environmental impacts linked to agricultural production like eutrophication or ecotoxicity. Methodological challenges still exist, like the assessment of direct and indirect land use change emissions and their attribution to the bioenergy production, or the influence of heavy metal flows on the bioenergy assessment. Another challenge is the implementation of a life cycle approach in certification or legislation schemes, as shown by the example of the Renewable Energy Directive of the European Union.     

Life cycle assessment in the minerals and metals sector: a critical review of selected issues and challenges

Background, aim and scope

The mining sector provides materials that are essential elements in a wide range of goods and services, which create value by meeting human needs. Mining and processing activities are an integral part of most complex material cycles so that the application of life cycle assessment (LCA) to minerals and metals has therefore gained prominence. In the past decade, increased use of LCA in the mineral and metal sector has advanced the scientific knowledge through the development of scientifically valid life cycle inventory databases. Though scientifically valid, LCA still needs to depend on several technical assumptions. In particular, measuring the environmental burden issues related to abiotic resource depletion, land use impacts and open-loop recycling within the LCA are widely debated issues. Also, incorporating spatial and temporal sensitivities in LCA, to make it a consistent scientific tool, is yet to be resolved. This article discusses existing LCA methods and proposed models on different issues in relation to minerals and metals sector.

Main features

A critical review was conducted of existing LCA methods in the minerals and metals sector in relation to allocation issues related to indicators of land use impacts, abiotic resource depletion, allocation in open-loop recycling and the system expansions and accounting of spatial and temporal dimension in LCA practice.

Results

Evolving a holistic view about these contentious issues will be presented with view for future LCA research in the minerals and metals industry. This extensive literature search uncovers many of the issues that require immediate attention from the LCA scientific community.

Discussion

The methodological drawbacks, mainly problems with inconsistencies in LCA results for the same situation under different assumptions and issues related to data quality, are considered to be the shortcomings of current LCA. In the minerals and metals sector, it is important to increase the objectivity of LCA by way of fixing those uncertainties, for example, in the LCA of the minerals and metals sector, whether the land use has to be considered in detail or at a coarse level. In regard to abiotic resource characterisation, the weighting and time scales to be considered become a very critical issue of judgement. And, in the case of open-loop recycling, which model will best satisfy all the stake holders? How the temporal and spatial dimensions should be incorporated into LCA is one of the biggest challenges ahead of all those who are concerned. Addressing these issues shall enable LCA to be used as a policy tool in environmental decision-making. There has been enormous debate with respect to on land use impacts, abiotic resource depletion, open-loop recycling and spatial and temporal dimensions, and these debates remain unresolved. Discussions aimed at bringing consensus amongst all the stake holders involved in LCA (i.e. industry, academia, consulting organisations and government) will be presented and discussed. In addition, a commentary of different points of view on these issues will be presented.

Conclusions

This review shall bring into perspective some of those contentious issues that are widely debated by many researchers. The possible future directions proposed by researchers across the globe shall be presented. Finally, authors conclude with their views on the prospects of LCA for future research endeavours.

Recommendations and outlook

Specific LCA issues of minerals and metals need to be investigated further to gain more understanding. To facilitate the future use of LCA as a policy tool in the minerals and metals sector, it is important to increase the objectivity with more scientific validity. Therefore, it is essential that the issues discussed in this paper are addressed to a great detail.     

Strategy tool trial for office furniture

Purpose

A strategic product development tool combining REACH and environmental and financial factors was previously developed for a coatings company. This paper presents results from refining this tool for an office furniture company, using life cycle assessment (LCA)-based environmental information, addressing the research questions: ? Is it possible to combine information from REACH with the LCA approach to provide useful information for a furniture producer in their environmental product development process? ? Does the approach developed for substances in mixtures need to be adapted for articles? ? Is there a correlation between energy consumption and the environmental impacts analysed? ? Will product designers get the same information independent of the environmental impact category used? ?C Will the strategy tool indicate the same ranking of products for all environmental impacts? ?C Does REACH information indicate the same set of priorities as those arising from LCA environmental data alone? (Do they agree, or is there a conflict?) ? Will strategic decisions differ if different environmental indicators are in focus? The strategy tool??s purpose is to analyse company product portfolios, identifying products that need redevelopment or redesign because of issues concerning hazardous substances, or environmental performance.

Methods

The LCA data used is cradle-to-gate data from type III environmental declarations for 11 seating solutions. REACH Complexity, health hazard and environmental class indicators (based on risk phrases) are combined with financial data and LCA-based indicators. Correlations between energy consumption and environmental impact factors for these specific furniture products are investigated. Establishing any such correlations serves to simplify subsequent analysis in the product development process, by effectively reducing the number of indicators that need to be taken into consideration.

Results

Correlations between energy consumption and the environmental impacts global warming, acidification, eutrophication and heavy metals are presented. Strategy tool figures are shown for energy consumption, ozone depletion potential and photochemical oxidation potential. The results for office chairs and conference/visitor chairs are presented separately, as the two types of chairs fulfil different functions.

Conclusions

The correlation between energy consumption and certain environmental impact indicators affords a simplification of the product development process, since energy consumption can be used as a reasonable proxy for these indicators in this specific case. The results support acknowledged principles of Ecodesign. Energy and materials minimization improves environmental performance??higher recycled material content and proportion of renewable energy resources are also beneficial. Designers have to consider multiple aspects in parallel and the strategy tool is useful for this purpose; the furniture producer has gained useful product development insight. The tool is applicable for strategic choice of products for development or redesign that can be useful across many business sectors.     

Dynamic life cycle assessment: framework and application to an institutional building

Purpose

This paper uses a dynamic life cycle assessment (DLCA) approach and illustrates the potential importance of the method using a simplified case study of an institutional building. Previous life cycle assessment (LCA) studies have consistently found that energy consumption in the use phase of a building is dominant in most environmental impact categories. Due to the long life span of buildings and potential for changes in usage patterns over time, a shift toward DLCA has been suggested.

Methods

We define DLCA as an approach to LCA which explicitly incorporates dynamic process modeling in the context of temporal and spatial variations in the surrounding industrial and environmental systems. A simplified mathematical model is used to incorporate dynamic information from the case study building, temporally explicit sources of life cycle inventory data and temporally explicit life cycle impact assessment characterization factors, where available. The DLCA model was evaluated for the historical and projected future environmental impacts of an existing institutional building, with additional scenario development for sensitivity and uncertainty analysis of future impacts.

Results and discussion

Results showed that overall life cycle impacts varied greatly in some categories when compared to static LCA results, generated from the temporal perspective of either the building's initial construction or its recent renovation. From the initial construction perspective, impacts in categories related to criteria air pollutants were reduced by more than 50 % when compared to a static LCA, even though nonrenewable energy use increased by 15 %. Pollution controls were a major reason for these reductions. In the future scenario analysis, the baseline DLCA scenario showed a decrease in all impact categories compared with the static LCA. The outer bounds of the sensitivity analysis varied from slightly higher to strongly lower than the static results, indicating the general robustness of the decline across the scenarios.

Conclusions

These findings support the use of dynamic modeling in life cycle assessment to increase the relevance of results. In some cases, decision making related to building design and operations may be affected by considering the interaction of temporally explicit information in multiple steps of the LCA. The DLCA results suggest that in some cases, changes during a building's lifetime can influence the LCA results to a greater degree than the material and construction phases. Adapting LCA to a more dynamic approach may increase the usefulness of the method in assessing the performance of buildings and other complex systems in the built environment.     

Significance of the use of non-renewable fossil CED as proxy indicator for screening LCA in the beverage packaging sector

Purpose

This study discusses the significance of the use of non-renewable fossil cumulative energy demand (CED) as proxy indicator in the beverage packaging sector, in order to detect those situations in which companies can benefit from the use of proxy indicators before a full life cycle assessment (LCA) application. Starting from a case study of two milk containers, the objectives of this paper are to assess if the use of this inventory indicator can be a suitable proxy indicator both (1) to decide which is the packaging alternative with the lowest environmental impact and (2) to identify the most impacting process units of the two products under study.

Method

The analysis was made according to ISO14040-44. The goal of the comparative LCA was to evaluate and to compare the potential environmental impacts from cradle to grave of a laminated carton container and a HDPE bottle. The results of the comparative LCA obtained with the non-renewable CED indicator are compared with a selection of impact categories: climate change, particulate matter formation, terrestrial acidification, fossil depletion, photochemical oxidant formation. A further analysis is made for the two products under study in order to determine which are the environmental hot spots in terms of life cycle stages, by the means of a contribution analysis.

Results and discussion

From the comparative LCA, the use of non-renewable CED revealed to be useful for a screening as the results given by the non-renewable CED indicator are confirmed by all the impact categories considered, even if underestimated. If the aim of the LCA study was to define which is the packaging solution with a lower environmental impact, the choice of this inventory indicator could have led to the same decision as if a comprehensive LCIA method was used. The contribution analysis, focusing on the identification of environmental hot spots in the packaging value chain, revealed that the choice of an inventory indicator as non-renewable CED can lead to misleading results, if compared with another impact category, such as climate change.

Conclusions

As in the future development of beverage packaging system, LCA will be necessarily integrated in the design process, it is important to define other ways of simplifying its application and spread its use among companies. The LCI indicator non-renewable fossil CED can effectively be used in order to obtain a preliminary estimation of the life cycle environmental impacts of two or more competing products in the beverage packaging sector.